The case for animal experiments will be harder to defend as a result of new guidelines from the Charity Commission, says the Association of Medical Research Charities.
The guidelines, issued last year, prohibit the sending of standard letters to supporters who sign them and post them en masse to MPs.
This could impede charities from responding to campaigns by animal rights organisations, which frequently lobby MPs in this way because they are not registered charities, the association says.
The guidelines are part of a document, Political Activities and Campaigning by Charities, which deals with the dividing line between political activity, which charities cannot by law engage in, and pursuing charitable objectives, which may necessitate activities in a political context.
Leslie Busk, association chairman, has written to the Charity Commission saying: "Many of the issues which concern us are complex. To present them with accuracy and clarity can require considerable time and drafting experience. It is approriate that the association should provide such a service for members. The association is concerned also that the charitable sector may be disadvantaged and sometimes unable to respond to opposing campaigns in an effective manner."
But Andrew Tyler, campaigns director of Animal Aid, said: "The charities can't have it both ways. They have economic advantages from their charitable status. They can't both cull the tax benefits and act to change the law through these political campaigning means. This is a decision that all groups that seek to advance a debate have to face."
The Research for Health Charities Group, which puts forward the case for animal experimentation on behalf of major medical charities, does not use standard letters at the moment. But director Myc Wriggulsford said: "There might come a time when we would want to use it so there is a point at issue here."
The association is also worried that it cannot lobby in the European Union using standard letters despite the fact that charities in other countries are allowed to. The Charity Commission said that it is reconsidering the issue. "If any charity is unclear we will give advice in particular cases," it said.
Sub-human treatment, page 19